The Effects of Hard Exercise on Muscle Function

If your muscles are damaged, they're sending signals back up through your central nervous system which help block signals from the brain. For example, that burning sensation that happens when you exercise is not actually lactic acid but metabolic byproducts of hard exercise. If all three rise at the same time, then that triggers an alarm bell that sends back a signal to your brain. So it's not that your muscles are failing. They're trying to alter your behavior and force you to slow down. It's really our brains and ability to tell our muscles what to do.